Jan 31, 2008 (CIDRAP News) School-based vaccination could be a cost-effective option for preventing influenza in school-age children and their families, according to a recent multistate trial.
The study, published Jan 23 in an early online edition of Health Affairs, used a population of more than 15,000 school children ages 5 to 18 from a previous study that showed the intranasal live attenuated influenza vaccine, FluMist, reduced flu-like illnesses in the households of children who were vaccinated. That study was conducted during the 2004-05 influenza season and was supported by MedImmune, the maker of FluMist.
The current study was designed to gauge whether school-based immunizations are cost-effective, according to the authors, led by Jordana Schmier, a managing scientist at Exponent, a research group based in Menlo Park, Calif. The trial grouped 28 elementary schools from four states into 11 demographically similar clusters, each of which included one intervention school that offered the vaccine plus one or two schools that served as controls. The vaccine was offered free of charge at school to all healthy children aged 5 or older during the fall of 2004.
Investigators did a cost-benefit analysis of the previous trial, which was published in a December 2006 issue of the New England Journal of Medicine. Phone surveys during the peak week of the flu season revealed that 17% of households of students in the intervention schools reported a child with flulike illness, compared with 26% of households in the control schools. In the same week, 8% of households in the intervention group reported an adult with a flu-like illnesses, compared with 13% in control-group households.
The authors of the new study used "event rate" data from the earlier studysuch as rates of medical visits, prescription drug purchases, and missed work daysto estimate the per-household costs of vaccination and costs related to flu cases. In intervention schools, where almost half of the students were vaccinated, peak-week vaccination costs were estimated at $41.66, compared to $5.58 in control schools, where about 2% of students reported vaccination outside school.
However, the researchers reported that the expense of the vaccine program was exceeded by the direct and indirect flu-related costs. During the peak influenza week, intervention households used $57.63 in healthcare resources to treat influenza infections, compared with $75.50 used by control households. For indirect costs such as care-giving and absences from school and work, intervention households spent $64.48 during the peak week of flu season, while control households spent $81.97.
The difference in costs during the peak flu season was smallonly 71 centsthe researchers reported. However, they said the difference would be magnified over the entire flu season, during which intervention households would incur an estimated total cost of $759.92, versus $931.88 for the control groupa difference of $171.96.
"The major cost disadvantage for intervention schools is the costs of the vaccine themselves," said Schmier in a Jan 23 Health Affairs press release. "But by peak week, most students who are going to be immunized have already received their vaccines, leaving intervention schools to reap savings from their higher vaccination rate for the rest of the flu season."
Previous studies on the cost-effectiveness of school-based immunizations have shown mixed results, the authors reported. However, none of them were designed to gather data about household protection due to vaccination of school-age children.
The authors wrote that their study supports two key points about vaccinating school-age children: "First, that its effectiveness extends to the household, and second, that a high-efficiency immunization program that requires minimal time from parents provides economic benefit."
Amanda Honeycutt, PhD, a health economist at RTI International, a research institute based in Triangle Park, N.C., has worked with the Centers for Disease Control and Prevention (CDC) on projects to improve immunization rates. She told CIDRAP News that the researchers established that if a school-based program immunizes a high percentage of students, the results could yield cost savings. (The immunization rate in the intervention schools was 47%.)
In a school-based immunization program, administration costs are lower and the cost of the vaccine is probably lower than in a physician's office, Honeycutt said. "A nurse can give this vaccine to 15 children an hour, and this does appear to be cost saving," she said, adding that in economic terms, "cost saving" is a high bar to pass.
The CDC's Advisory Committee on Immunization Practices (ACIP) will meet in February to update its flu immunization recommendations. In a February 2006 press release, the CDC said it would continue to review vaccination strategies to improve flu prevention and control, including the possibility of expanding routine vaccination recommendations to the entire US population.
Among other strategies for boosting flu immunization rates in children, New Jersey in December became the first state to require flu shots for preschool children, according to a Dec 14 Associated Press report. The rule takes effect on Sep 1 and also covers three other vaccines for children, including the pneumococcal vaccine for preschoolers and the meningitis vaccine and whooping cough booster for 6th graders.
Some parent groups opposed the new regulations because of concerns about vaccine safety and the role of the government in making medical decisions, the AP report said. The New Jersey laws grant religious and medical exemptions.
Schmier J, Li S, King JC, et al. Benefits and costs of immunizing children against influenza at school: an economic analysis based on a large-cluster controlled clinical trial. Health Affairs 2008;27(2)(early online publication) [Abstract]
King JC, Stoddard JJ, Gaglani MJ, et al. Effectiveness of school-based influenza vaccination. N Engl J Med 2006;355(24):2523-32 [Full text]
Health Affairs press release
Feb 23, 2006, CDC press release
Dec 14, 2006, CIDRAP News story "Studies support flu vaccination in children, adults"